:root{
  box-sizing:border-box;
  padding-top:env(safe-area-inset-top,0px);
  padding-bottom:env(safe-area-inset-bottom,0px);
  color-scheme:dark;
  --bg:#060913; --ink:#e9edf8; --dim:#8b95b5; --line:rgba(255,255,255,.09);
  --mint:#5cf2b0; --coral:#ff6b6b; --violet:#8b6cff; --amber:#ffc857; --blue:#5b7cff; --pink:#ff5fa2;
  --ui:'Sora',system-ui,-apple-system,'Segoe UI',sans-serif;
  --math:'STIX Two Text','Cambria Math','Times New Roman',serif;
}
html{scroll-padding-top:env(safe-area-inset-top,0px);scroll-behavior:smooth}
*,*::before,*::after{box-sizing:border-box}
body{
  margin:0;min-height:100vh;color:var(--ink);font-family:var(--ui);font-size:14px;line-height:1.55;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
  background:
    radial-gradient(60% 50% at 10% 0%,rgba(92,242,176,.16),transparent 62%),
    radial-gradient(55% 45% at 92% 6%,rgba(139,108,255,.22),transparent 62%),
    radial-gradient(50% 40% at 58% 100%,rgba(255,107,107,.10),transparent 62%),
    var(--bg);
  background-attachment:fixed;
}
@keyframes cardIn{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}
@media (prefers-reduced-motion:reduce){*,*::before,*::after{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important;scroll-behavior:auto!important}}
body::before{
  content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;
  background-image:linear-gradient(rgba(255,255,255,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.035) 1px,transparent 1px);
  background-size:44px 44px;
  -webkit-mask-image:radial-gradient(80% 70% at 50% 30%,#000 30%,transparent 100%);
  mask-image:radial-gradient(80% 70% at 50% 30%,#000 30%,transparent 100%);
}
.wrap{max-width:1320px;margin:0 auto;padding:22px 20px 40px}
header{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:20px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:12px}
.brand h1{font-family:var(--math);font-weight:600;font-size:30px;letter-spacing:.01em;margin:0;line-height:1}
.brand p{margin:2px 0 0;color:var(--dim);font-size:12.5px}
.tag{font-size:12px;color:var(--dim);border:1px solid var(--line);border-radius:999px;padding:5px 12px;background:rgba(255,255,255,.03)}
.layout{display:grid;grid-template-columns:390px minmax(0,1fr);grid-template-areas:"matrix viz" "results viz";gap:18px;align-items:start}
.glass{background:rgba(255,255,255,.04);border:1px solid var(--line);border-radius:20px;padding:18px;backdrop-filter:blur(18px);-webkit-backdrop-filter:blur(18px);box-shadow:0 20px 50px -30px rgba(0,0,0,.8);animation:cardIn .38s cubic-bezier(.16,1,.3,1);transition:box-shadow .25s ease,border-color .25s ease}
#matrix{grid-area:matrix}#results{grid-area:results}#viz{grid-area:viz;position:sticky;top:16px}
h2{font-size:13px;font-weight:600;margin:0 0 12px;color:var(--ink);letter-spacing:.01em}
.seg{display:inline-flex;background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:999px;padding:3px}
.seg button{font:inherit;font-size:12.5px;color:var(--dim);background:none;border:0;border-radius:999px;padding:5px 13px;cursor:pointer;transition:color .15s ease,background-color .15s ease}
.seg button[aria-pressed=true]{background:rgba(92,242,176,.16);color:var(--mint)}
button:focus-visible,input:focus-visible{outline:2px solid var(--mint);outline-offset:2px}
button,.chip,.btn{transition:color .15s ease,background-color .15s ease,border-color .15s ease,transform .15s ease}
.chip:active,.btn:active{transform:scale(.96)}
.mxwrap{display:flex;justify-content:center;margin:18px 0 14px}
.mx{display:grid;gap:8px;position:relative;padding:8px 20px}
.mx::before,.mx::after{content:"";position:absolute;top:0;bottom:0;width:10px;border:2px solid #9aa6d1}
.mx::before{left:0;border-right:0;border-radius:6px 0 0 6px}
.mx::after{right:0;border-left:0;border-radius:0 6px 6px 0}
.mx input{width:74px;font-family:var(--math);font-size:22px;text-align:center;color:var(--ink);background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:10px;padding:8px 4px}
.mx input.bad{border-color:var(--coral);color:var(--coral)}
.chips{display:flex;flex-wrap:wrap;gap:6px}
.chip{font:inherit;font-size:12px;color:var(--ink);background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:999px;padding:4px 11px;cursor:pointer}
.chip:hover{border-color:rgba(92,242,176,.5)}
.hint{color:var(--dim);font-size:12px;margin:10px 0 0}
.hero{display:flex;gap:16px;align-items:center;margin-bottom:14px}
.rk{font-family:var(--math);font-size:64px;line-height:1;color:var(--mint);min-width:44px;text-align:center}
.hero .h{font-weight:600}
.strip{margin:6px 0 4px;display:flex}
.strip i{display:block;width:28px;height:9px;border-radius:5px;margin-right:5px}
.strip i.on{background:var(--mint)}.strip i.off{border:1.5px dashed var(--coral)}
.cap{font-size:12px;color:var(--dim)}
dl.facts{display:grid;grid-template-columns:auto 1fr;gap:6px 14px;margin:0 0 14px;padding-top:12px;border-top:1px solid var(--line)}
dl.facts dt{color:var(--dim)}dl.facts dd{margin:0;text-align:right;font-family:var(--math);font-size:16px}
dd small{font-family:var(--ui);font-size:11.5px;color:var(--dim);display:block;line-height:1.3}
.yes{color:var(--mint)}.no{color:var(--coral)}
.rrefbox{display:flex;justify-content:center;margin:8px 0 10px}
.rref{display:grid;gap:4px 6px;position:relative;padding:6px 18px}
.rref::before,.rref::after{content:"";position:absolute;top:0;bottom:0;width:9px;border:2px solid #9aa6d1}
.rref::before{left:0;border-right:0;border-radius:6px 0 0 6px}.rref::after{right:0;border-left:0;border-radius:0 6px 6px 0}
.rref span{font-family:var(--math);font-size:19px;min-width:52px;text-align:center;padding:3px 6px;border-radius:8px;border:1px solid transparent}
.rref span.pv{border-color:var(--mint);background:rgba(92,242,176,.12);color:var(--mint)}
.sub{font-size:12.5px;color:var(--dim);margin:6px 0}
.sub b{color:var(--ink);font-weight:500}
.rel{font-family:var(--math);font-size:16px;margin:4px 0}
.pair{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.cvcell h3{margin:0 0 6px;font-size:12.5px;font-weight:500;color:var(--dim);display:flex;justify-content:space-between}
.cvcell h3 em{font-family:var(--math);font-style:italic;color:var(--ink);font-size:15px}
canvas{display:block;width:100%;aspect-ratio:1/1;border-radius:14px;border:1px solid var(--line);background:rgba(4,6,14,.6)}
canvas.clickable3d{cursor:pointer}
.gotab4{font:inherit;font-size:11.5px;color:#5cf2b0;background:rgba(92,242,176,.1);border:1px solid rgba(92,242,176,.35);border-radius:999px;padding:3px 10px;cursor:pointer;margin-left:2px}
#cout,#cex{touch-action:none}
.ctrl{display:flex;flex-wrap:wrap;gap:14px 24px;align-items:center;margin:14px 0 4px}
.ctrl label{display:flex;align-items:center;gap:10px;color:var(--dim);font-size:12.5px}
.ctrl input[type=range]{accent-color:var(--mint);width:150px}
.btn{font:inherit;font-size:12.5px;color:var(--ink);background:rgba(92,242,176,.12);border:1px solid rgba(92,242,176,.4);border-radius:999px;padding:6px 14px;cursor:pointer}
.legend{display:flex;flex-wrap:wrap;gap:6px 16px;font-size:12px;color:var(--dim);margin:8px 0 0}
.legend span::before{content:"";display:inline-block;width:10px;height:10px;border-radius:3px;margin-right:6px;background:var(--c);vertical-align:-1px}
.legend span.dash::before{background:none;border:1.5px dashed var(--c)}
#explain{margin-top:14px;padding-top:12px;border-top:1px solid var(--line);font-size:13.5px}
#explain p{margin:0 0 6px}#explain .m{font-family:var(--math);font-size:16px}
[hidden]{display:none!important}
#p2{grid-template-areas:"vecs viz" "ops viz" "span viz"}
#vecs{grid-area:vecs}#ops{grid-area:ops}#span{grid-area:span}#vizE{grid-area:viz;position:sticky;top:16px}
.eh{margin:0 0 8px;font-size:12.5px;font-weight:500;color:var(--dim)}
.vrow{display:grid;grid-template-columns:auto 1fr auto auto auto;gap:8px;align-items:center;padding:7px 0;border-bottom:1px solid var(--line)}
.vrow.off .vn,.vrow.off .vin{opacity:.45}
.vrow .eye{accent-color:var(--mint);width:16px;height:16px}
.vn b{font-family:var(--math);font-size:19px;font-weight:600;display:block;line-height:1.1}
.vn small{color:var(--dim);font-size:11.5px}
.vin{width:62px;font-family:var(--math);font-size:18px;text-align:center;color:var(--ink);background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:10px;padding:6px 3px}
.vin.bad{border-color:var(--coral);color:var(--coral)}
.vrow .x{font:inherit;font-size:18px;line-height:1;width:28px;height:28px;color:var(--dim);background:none;border:1px solid var(--line);border-radius:50%;cursor:pointer}
.vrow .x:hover{color:var(--coral);border-color:var(--coral)}
.chip:disabled,.btn:disabled,.seg button:disabled{opacity:.4;cursor:default}
.sel{display:flex;gap:18px;margin-bottom:10px}
.sel label{display:flex;align-items:center;gap:8px;font-family:var(--math);font-size:17px;font-style:italic}
select{font:inherit;font-size:13px;color:var(--ink);background:#0d1224;border:1px solid var(--line);border-radius:10px;padding:5px 8px}
.sl{display:grid;grid-template-columns:18px 1fr 44px;align-items:center;gap:10px;margin:8px 0;font-family:var(--math);font-style:italic;font-size:17px}
.sl input{accent-color:var(--mint);width:100%}
.sl output{font-family:var(--ui);font-style:normal;font-size:12.5px;color:var(--dim);text-align:right}
.chk{display:flex;gap:8px;align-items:center;font-size:12.5px;color:var(--dim);margin:12px 0 0}
.chk input{accent-color:var(--mint)}
.expr{overflow-x:auto;padding:8px 0 2px;margin-top:6px;border-top:1px solid var(--line)}
.expr math{font-family:var(--math);font-size:1.15em}
.edu{margin:8px 0 0;font-size:13.5px}
@media (max-width:980px){
  .layout{grid-template-columns:minmax(0,1fr);grid-template-areas:"matrix" "viz" "results"}
  #viz,#vizE{position:static}
  #p2{grid-template-areas:"vecs" "viz" "ops" "span"}
}
@media (max-width:620px){.pair{grid-template-columns:1fr}.wrap{padding:16px 12px 32px}.mx input{width:64px}}
@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}
/* ===== Phase 3: row reduction ===== */
.stack{display:grid;gap:18px;min-width:0;align-content:start}
#p3{grid-template-columns:400px minmax(0,1fr);grid-template-areas:none}
#rin{order:1}#rstep{order:2}#rres{order:3}#rgeo{order:4}
.rsz{margin:12px 0 0;justify-content:center}
.opts{display:flex;flex-wrap:wrap;gap:8px 12px;align-items:center;margin-top:14px;font-size:12.5px;color:var(--dim)}
.opt{display:flex;align-items:center;gap:8px}
.opts .seg button{font-size:12px;padding:4px 11px}
#rmx input.long{font-size:14px}
.rhead{display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:6px}
.rhead h2{margin:0}
.phase{font-size:12.5px;color:var(--dim);display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap}
.phase b{color:var(--ink);font-weight:500}
.rrefbox{overflow-x:auto}
.rrefbox>.rref{margin:0 auto}
.rref.rows{display:flex;flex-direction:column;gap:4px;padding:8px 20px}
.mrow{display:grid;grid-template-columns:repeat(var(--n),var(--cw,56px));gap:6px;border-radius:9px;padding:2px 0}
.rref .mrow span{width:var(--cw,56px);min-width:0;padding:5px 2px;font-size:20px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;transition:background .2s,border-color .2s}
.mrow.prow{background:rgba(92,242,176,.07)}
.mrow.tgt{background:rgba(255,200,87,.10);box-shadow:inset 0 0 0 1px rgba(255,200,87,.35)}
.mrow.flash{animation:rflash .9s ease-out}
@keyframes rflash{from{background:rgba(255,200,87,.38)}to{background:rgba(255,200,87,.10)}}
.rref .mrow span.pcol{background:rgba(139,108,255,.14)}
.rref .mrow span.pv{border-color:var(--mint);background:rgba(92,242,176,.14);color:var(--mint)}
.rref .mrow span.cur{box-shadow:0 0 0 2px rgba(92,242,176,.55)}
.rref .mrow span.nopv{border-color:var(--coral);box-shadow:0 0 0 2px rgba(255,107,107,.35)}
.opline{font-family:var(--math);font-size:24px;text-align:center;margin:8px 0 0;min-height:36px}
.rctl{margin:6px 0 4px;justify-content:center;gap:8px}
.btn.alt{background:rgba(255,255,255,.05);border-color:var(--line)}
.scrub{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:12px;align-items:center;font-size:12.5px;color:var(--dim)}
.scrub input{accent-color:var(--mint);width:100%}
#redu{margin-top:10px;padding-top:12px;border-top:1px solid var(--line)}
#redu p{margin:0 0 8px;font-size:13.5px}
#redu dl.facts{margin:6px 0 0;padding-top:10px}
.mid{color:var(--dim)}
.geo{display:grid;grid-template-columns:minmax(0,420px) minmax(0,1fr);gap:18px;align-items:start}
.geo.nocv{grid-template-columns:minmax(0,1fr)}
.colrow{display:flex;gap:12px;align-items:baseline;padding:8px 0;border-bottom:1px solid var(--line);font-family:var(--math);font-size:16px}
.colrow b{color:var(--c);font-size:19px;min-width:26px}
.colrow small{display:block;font-family:var(--ui);font-size:11.5px;color:var(--dim);line-height:1.35}
.legend span.ring::before{background:none;border:2px solid var(--c);border-radius:50%}
.rnote{font-size:12.5px;color:var(--dim);margin:10px 0 0}
.rnote b{color:var(--ink);font-weight:500}
@media (max-width:980px){
  #p3{grid-template-columns:minmax(0,1fr)}
  #p3 .stack{display:contents}
  .geo{grid-template-columns:minmax(0,1fr)}
  #rcv{max-width:460px;margin:0 auto}
}
@media (max-width:620px){.rref .mrow span{font-size:17px}.rref.rows{padding:8px 16px}.opline{font-size:20px}}
/* ===== Phase 4: 3D, null space, footer, legal ===== */
.p4{grid-template-columns:minmax(0,1fr) minmax(0,1fr);grid-template-areas:"v3vecs v3viz" "m3in m3viz" "nsin nsviz"}
#v3vecs{grid-area:v3vecs}#v3viz{grid-area:v3viz}#m3in{grid-area:m3in}#m3viz{grid-area:m3viz}#nsin{grid-area:nsin}#nsviz{grid-area:nsviz}
@media (max-width:980px){.p4{grid-template-columns:minmax(0,1fr);grid-template-areas:"v3vecs" "v3viz" "m3in" "m3viz" "nsin" "nsviz"}}
.c3wrap{position:relative;border-radius:14px;overflow:hidden;border:1px solid var(--line);background:rgba(4,6,14,.6)}
.c3wrap canvas{display:block;width:100%;aspect-ratio:4/3;touch-action:none;cursor:grab}
.c3wrap canvas:active{cursor:grabbing}
.c3load{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;color:var(--dim);font-size:12.5px;background:rgba(4,6,14,.6);transition:opacity .25s}
.c3load[hidden]{display:none}
.vrow3{display:grid;grid-template-columns:auto 1fr auto auto auto auto;gap:8px;align-items:center;padding:7px 0;border-bottom:1px solid var(--line)}
.vrow3.off .vn,.vrow3.off .vin{opacity:.45}
.vrow3 .eye{accent-color:var(--mint);width:16px;height:16px}
.vrow3 .x{font:inherit;font-size:18px;line-height:1;width:28px;height:28px;color:var(--dim);background:none;border:1px solid var(--line);border-radius:50%;cursor:pointer}
.vrow3 .x:hover{color:var(--coral);border-color:var(--coral)}
.nsrow{display:flex;align-items:baseline;gap:10px;padding:6px 0;border-bottom:1px solid var(--line);font-family:var(--math);font-size:15px}
.nsrow b{color:var(--mint);min-width:70px}
.nstag{font-size:11px;color:var(--dim);border:1px solid var(--line);border-radius:999px;padding:2px 9px;margin-right:6px;display:inline-block}
.rntheorem{font-family:var(--math);font-size:19px;text-align:center;margin:10px 0;padding:12px;border:1px solid var(--line);border-radius:12px;background:rgba(92,242,176,.05)}
.rntheorem .ok{color:var(--mint)}
/* footer */
.ad-slot{background:rgba(255,255,255,.03);border:1px solid var(--line);border-radius:16px;padding:10px 14px;margin:18px 0;text-align:center;overflow:hidden}
.ad-slot-label{display:block;font-size:10.5px;letter-spacing:.08em;text-transform:uppercase;color:var(--dim);margin-bottom:6px}
.ad-slot.ad-header{margin:0 0 16px}
.ad-slot.ad-footer{margin:22px 0 0}
.sitefoot{margin-top:34px;border-top:1px solid var(--line);padding-top:10px}
.footwrap{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:22px;padding-top:22px;padding-bottom:8px}
.footcol .brand{margin-bottom:10px}
.footcol .brand b{font-family:var(--math);font-size:17px}
.footcol .brand p{margin:2px 0 0;color:var(--dim);font-size:11.5px}
.footcol h4{margin:0 0 8px;font-size:12px;color:var(--dim);font-weight:500;letter-spacing:.02em;text-transform:uppercase}
.footcol p{margin:0 0 6px;font-size:12.5px;color:var(--dim);line-height:1.5}
.ai-disclosure{font-size:11.5px;color:var(--dim);margin-top:10px;line-height:1.5}
.legal-link{display:block;font-size:12.5px;color:var(--ink);text-decoration:none;margin-bottom:8px;opacity:.85}
.legal-link:hover{color:var(--mint);opacity:1;text-decoration:underline}
.endnote{max-width:1320px;margin:14px auto 0;padding:14px 20px 26px;text-align:center;font-family:var(--math);font-style:italic;color:var(--dim);font-size:13px;border-top:1px solid var(--line)}
.comingsoon{max-width:480px;margin:60px auto;text-align:center;padding:48px 32px}
.comingsoon h2{margin:0 0 10px}
.comingsoon-msg{font-family:var(--math);font-size:28px;color:var(--mint);margin:0 0 12px}
@media (max-width:700px){.footwrap{grid-template-columns:1fr;gap:18px}}
/* legal overlay */
.legaloverlay{position:fixed;inset:0;z-index:50;background:rgba(4,6,14,.92);backdrop-filter:blur(6px);overflow-y:auto;padding:26px 16px}
.legalcard{max-width:760px;margin:0 auto;padding:26px 26px 32px}
.legalclose{margin-bottom:16px}
#legalContent h2{font-family:var(--math);font-size:24px;margin:0 0 4px}
#legalContent .upd{color:var(--dim);font-size:12px;margin:0 0 18px}
#legalContent h3{font-size:14px;margin:20px 0 6px;color:var(--ink)}
#legalContent p,#legalContent li{font-size:13.5px;color:var(--dim);line-height:1.6}
#legalContent ul{margin:6px 0;padding-left:20px}
#legalContent a{color:var(--mint)}
/* #sm-app-specific ---------------------------------------------------- */
.sm-title{margin:0 0 14px}
.sm-title h2{margin:0 0 4px}
.sm-title .hint{margin:0}
.calc-stack{margin-top:18px}
.sm-panel[hidden]{display:none}
.sm-row{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-bottom:12px}
.sm-row label{display:flex;align-items:center;gap:8px;color:var(--dim);font-size:12.5px}
.sm-row input{width:150px;font-family:var(--math);font-size:16px;color:var(--ink);background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:10px;padding:7px 10px}
.sm-row input#sm-var,.sm-row input#sm2-var,.sm-row input#sm3-var{width:48px;text-align:center}
.sm-mathbox{min-width:170px;max-width:100%;overflow-x:auto;white-space:nowrap;font-family:var(--math);font-size:16px;color:var(--ink);background:rgba(255,255,255,.05);border:1px solid var(--line);border-radius:10px;padding:7px 10px;cursor:text}
.sm-mathbox:focus{outline:2px solid var(--mint);outline-offset:1px;border-color:transparent}
.sm-mathbox .sm-pow{font-size:.65em;vertical-align:super;padding:0 3px;margin:0 1px;border-radius:4px;background:rgba(92,242,176,.14);border:1px solid rgba(92,242,176,.4);color:var(--mint)}
.hint{color:var(--dim);font-size:12px;margin:4px 0 14px}
code{font-family:var(--math);background:rgba(255,255,255,.06);border-radius:4px;padding:0 4px}
.sm-status{font-size:12.5px;margin:4px 0 0;text-align:left}
.sm-status.err{color:var(--coral)}
.sm-status.ok{color:var(--mint)}
.sm-step{border-top:1px solid var(--line);padding:12px 0;text-align:left}
.sm-step:first-child{border-top:0;padding-top:0}
.sm-step h3{margin:0 0 4px;font-size:13px;font-weight:600;color:var(--mint);text-align:left}
.sm-step p{margin:0 0 6px;color:var(--ink);text-align:left}
.sm-step .sm-expr{display:flex;flex-wrap:wrap;justify-content:flex-start;align-items:baseline;gap:.15em .55em;max-width:100%;overflow-x:auto;-webkit-overflow-scrolling:touch;padding-bottom:2px;font-family:var(--math);font-size:16px;color:var(--violet);text-align:left}
.sm-step .sm-expr .sm-term{display:inline-block;white-space:nowrap;margin:0}
.sm-step .sm-expr math{font-family:var(--math);font-size:1.15em;color:var(--violet);margin:0;text-align:left}
.sm-step .sm-expr-err{color:var(--dim);font-family:var(--ui);font-size:12px;white-space:normal;word-break:break-word}
.sm-divsign{color:var(--dim);font-family:var(--mat